I've been learning Moose and I came across unexpected behavior: method
modifiers (such as 'after') do not seem to work with attribute triggers. This
is an issue because I want a subclass to extend a method that is defined as a
trigger in the parent. The issue and one workaround is shown below.
use strict;use warnings;
package Foo;
use Moose;
has 'attrib' => ( is => 'rw', trigger => \&attrib_changed );has 'workaround' =>
( is => 'rw', trigger => \&workaround_changed );
sub attrib_changed{ print " in attrib_changed\n"; # called}
after 'attrib_changed' => sub{ print " in 'after' attrib_changed\n"; #
not called};
sub workaround_changed{ my ( $self ) = @_; print " in
workaround_changed\n"; # called $self->not_a_trigger;}
after 'workaround_changed' => sub{ print " in 'after'
workaround_changed\n"; # not called};
sub not_a_trigger{ print " in not_a_trigger\n"; # called}
after 'not_a_trigger' => sub{ print " in 'after' not_a_trigger\n"; #
called};
my $foo = Foo->new;
print "Calling attrib( 1 ):\n";$foo->attrib( 1 );
print "Calling workaround( 1 ):\n";$foo->workaround( 1 );
Output:
Calling attrib( 1 ): in attrib_changedCalling workaround( 1 ): in
workaround_changed in not_a_trigger in 'after' not_a_trigger
I could not find anything in the Moose docs or online that documents this
behavior as a known limitation. I'd be surprised if I were the first one to
notice it, so it makes me wonder whether I am trying to do something that is
best done some other way. Thoughts?
